linux/tools/perf/util/cpumap.h

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perf tools: Fix sparse CPU numbering related bugs At present, the perf subcommands that do system-wide monitoring (perf stat, perf record and perf top) don't work properly unless the online cpus are numbered 0, 1, ..., N-1. These tools ask for the number of online cpus with sysconf(_SC_NPROCESSORS_ONLN) and then try to create events for cpus 0, 1, ..., N-1. This creates problems for systems where the online cpus are numbered sparsely. For example, a POWER6 system in single-threaded mode (i.e. only running 1 hardware thread per core) will have only even-numbered cpus online. This fixes the problem by reading the /sys/devices/system/cpu/online file to find out which cpus are online. The code that does that is in tools/perf/util/cpumap.[ch], and consists of a read_cpu_map() function that sets up a cpumap[] array and returns the number of online cpus. If /sys/devices/system/cpu/online can't be read or can't be parsed successfully, it falls back to using sysconf to ask how many cpus are online and sets up an identity map in cpumap[]. The perf record, perf stat and perf top code then calls read_cpu_map() in the system-wide monitoring case (instead of sysconf) and uses cpumap[] to get the cpu numbers to pass to perf_event_open. Signed-off-by: Paul Mackerras <paulus@samba.org> Cc: Anton Blanchard <anton@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> LKML-Reference: <20100310093609.GA3959@brick.ozlabs.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-10 09:36:09 +00:00
#ifndef __PERF_CPUMAP_H
#define __PERF_CPUMAP_H
#include <stdio.h>
#include <stdbool.h>
#include <linux/atomic.h>
#include "perf.h"
#include "util/debug.h"
struct cpu_map {
atomic_t refcnt;
int nr;
int map[];
};
struct cpu_map *cpu_map__new(const char *cpu_list);
struct cpu_map *cpu_map__empty_new(int nr);
struct cpu_map *cpu_map__dummy_new(void);
struct cpu_map *cpu_map__new_data(struct cpu_map_data *data);
struct cpu_map *cpu_map__read(FILE *file);
size_t cpu_map__snprint(struct cpu_map *map, char *buf, size_t size);
size_t cpu_map__fprintf(struct cpu_map *map, FILE *fp);
int cpu_map__get_socket_id(int cpu);
int cpu_map__get_socket(struct cpu_map *map, int idx, void *data);
int cpu_map__get_core_id(int cpu);
int cpu_map__get_core(struct cpu_map *map, int idx, void *data);
int cpu_map__build_socket_map(struct cpu_map *cpus, struct cpu_map **sockp);
int cpu_map__build_core_map(struct cpu_map *cpus, struct cpu_map **corep);
struct cpu_map *cpu_map__get(struct cpu_map *map);
void cpu_map__put(struct cpu_map *map);
static inline int cpu_map__socket(struct cpu_map *sock, int s)
{
if (!sock || s > sock->nr || s < 0)
return 0;
return sock->map[s];
}
static inline int cpu_map__id_to_socket(int id)
{
return id >> 16;
}
static inline int cpu_map__id_to_cpu(int id)
{
return id & 0xffff;
}
static inline int cpu_map__nr(const struct cpu_map *map)
{
return map ? map->nr : 1;
}
static inline bool cpu_map__empty(const struct cpu_map *map)
{
return map ? map->map[0] == -1 : true;
}
int cpu__setup_cpunode_map(void);
int cpu__max_node(void);
int cpu__max_cpu(void);
int cpu__get_node(int cpu);
int cpu_map__build_map(struct cpu_map *cpus, struct cpu_map **res,
int (*f)(struct cpu_map *map, int cpu, void *data),
void *data);
bool cpu_map__has(struct cpu_map *cpus, int cpu);
perf tools: Fix sparse CPU numbering related bugs At present, the perf subcommands that do system-wide monitoring (perf stat, perf record and perf top) don't work properly unless the online cpus are numbered 0, 1, ..., N-1. These tools ask for the number of online cpus with sysconf(_SC_NPROCESSORS_ONLN) and then try to create events for cpus 0, 1, ..., N-1. This creates problems for systems where the online cpus are numbered sparsely. For example, a POWER6 system in single-threaded mode (i.e. only running 1 hardware thread per core) will have only even-numbered cpus online. This fixes the problem by reading the /sys/devices/system/cpu/online file to find out which cpus are online. The code that does that is in tools/perf/util/cpumap.[ch], and consists of a read_cpu_map() function that sets up a cpumap[] array and returns the number of online cpus. If /sys/devices/system/cpu/online can't be read or can't be parsed successfully, it falls back to using sysconf to ask how many cpus are online and sets up an identity map in cpumap[]. The perf record, perf stat and perf top code then calls read_cpu_map() in the system-wide monitoring case (instead of sysconf) and uses cpumap[] to get the cpu numbers to pass to perf_event_open. Signed-off-by: Paul Mackerras <paulus@samba.org> Cc: Anton Blanchard <anton@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> LKML-Reference: <20100310093609.GA3959@brick.ozlabs.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-10 09:36:09 +00:00
#endif /* __PERF_CPUMAP_H */